Laser range finders are becoming an increasingly vital component in high precision targeting engagements for the military. The precise and accurate range to target information is an essential variable to the fire control equation of all future soldier weapons. This information is easily, and timely, provided by laser range finders.
A critical component of the military laser range finder is the laser source. Military laser range finders must have robust performance in severe conditions, not only poor weather but also battlefield conditions. A high power, compact, low cost laser source is required by military laser range finders. As an example, the Er:Yb:Glass laser cavity with a scanning element as the optical Q-switch that is a short-pulse, eye safe laser meets the requirements for the military laser range finder's laser source.
The laser cavity with a single-axis scanning element as the optical Q-switch makes the development/fabrication of a very low cost, compact, short range laser range finder feasible. For example, if the laser media is Er:Yb:Glass then the laser diode (or flash lamp) pump radiation is converted directly to the desired eye safe wavelength of about 1535 nm (an Optical Parametric Oscillator is not needed!). The quality of the output laser from a Er:Yb:Glass laser cavity is of generally very good quality and thus requires minimum sized optics for adequate collimation of the beam for use in a laser range finder system.
Regrettably, during the manufacturing/fabrication alignment process of the optical laser cavity of the laser cavity with a single-axis scanning element as the optical Q-switch, there are small angular shifts in the optical axis due to the bonding process of the optical elements. These small angular shifts to the optical axis introduce laser cavity alignment errors which results in a decrease in output energy and beam quality.